1. Field of the Invention
The present invention relates to an apparatus for individually controlling the intensity of multiple lighting groups, and more specifically, relates to a control system which allows many groups of lights to be controlled with few controls.
2. Description of the Related Art
In many situations where artificial lighting is used to create an environment conducive to a variety of activities, such as in a hotel lobby; or where it is desirable to emphasize certain features or areas in an architectural space, it is advantageous to be able to control the incident light intensity of the areas independently, so that lighting can be optimized in each area. Areas may be illuminated by groups (or "zones") of lighting fixtures that are controlled together. A control panel, adapted to control power (and, thus, light intensity) to each zone, provides a convenient way to create a desired ambience or "scene"; i.e., a particular combination of zone intensities.
A typical control panel designed to provide this function incorporates an array of slide actuators, each of which controls the light output of a zone. A scene can be created by setting the position of each slide actuator in the array to a desired level. More versatile control panels typically include more than one array of slide actuators to provide additional scenes. A selector knob or push buttons are used to select among the preset scenes that are mechanically stored as arrays of slide actuator positions.
An Aurora.RTM. control panel, manufactured by Lutron Electronics, Coopersburg, Pa., provides four arrays of six slide actuators for controlling up to six zones of lights. Because it is desirable to keep the wall-mounted control panel small and simple, electronic signals are sent to a remote dimming cabinet which dims each zone to the instructed level. The remote cabinet may be mounted in an electrical closet, where load wires are more accessible and heat dissiptation is less of a problem. Any one of four preset scenes are recalled by actuating corresponding push buttons.
It is often desirable to control a large number of zones and create many preset scenes that can be recalled later. If, for instance, twenty-four zones of lights were to be controlled, with eight possible preset scenes, a control panel similar to the Aurora.RTM. would have eight arrays, each containing twenty-four slide actuators, for a total of 192 slide actuators. Unfortunately, a panel this large would be bulky, cumbersome to use, and costly to produce.
Some other control panels employ a single array of slide actuators to independently adjust lighting zone intensities; i.e., only one slide actuator is used per zone. Preset scenes are stored in an electronic memory, such as a static RAM integrated circuit chip. The Series-7, manufactured by Prescolite Controls, of Carrollton, Texas, incorporates a single array of twelve slide actuators, to control the same number of zones, and an electronic memory for storing up to eleven preset scenes. Once a scene is set via the actuator array, it can be stored in an electronic memory by pressing a "record" button, thereby storing the position of each actuator in the array. Scenes are recalled by pressing the corresponding scene buttons.
One disadvantage of this control system is that scenes cannot be "fine-tuned". Suppose, for example, that you have consecutively set a number of scenes to your liking. In reviewing scene one, you decide that zone five requires adjustment. At this point, the slide actuator array corresponds to the most recently set scene, even though the lighting corresponds to scene one. In order to make this correction to scene one, you must readjust all slide actuators to create a new scene one and record it over the old scene. This can be quite a nuisance, for example, when twenty-four zones of lights are being controlled and more than a few fine adjustments are required.
To overcome this inconvenience and to create a simpler control, the Omega control system, manufactured by Electronics Diversified, of Hillsboro, Oregon, incorporates an encoder wheel, which provides a single intensity adjustment for all zones. Zones within a scene are adjusted by selecting the appropriate zone, adjusting the zone intensity via the encoder wheel, and then actuating the record button to store the change. Thus, it is possible to select, adjust, and record a single zone change in a prerecorded scene without affecting the rest of the scene.
In some applications, especially in public buildings, it is advantageous to be able to prevent present scenes from being erased or altered. A control panel with a key locking mechanism can limit access to scene-record actuators. In other circumstances, it is necessary to create new scenes, but desirable to retain the originals (set by the lighting designer, for example). The Omega control system includes a disk storage and recall system, which allows scenes to be stored on magnetic disks. The disks may then be kept in a separate location.